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narrow and wide baffles and imaging

According to all the "professional" audio reviews that I've read over the last several years, narrow baffles are crucial to creating that so-desired pin-point imaging.

However, over the last few weeks, I've had the opportunity to audition Harbeth 40.2, Spendor Classic 100, Audio Note AN-E, and Devore O/93.  None of these had deficient imaging; indeed I would go so far as to say that it was good to very good.

So, what gives?  I'm forced to conclude that modern designs, 95% of which espouse the narrow baffle, are driven by aesthetic/cosmetic considerations, rather than acoustical ones, and the baffle~imaging canard is just an ex post facto justification.

I can understand the desire to build speakers that fit into small rooms, are relatively unobtrusive, and might pass the SAF test, but it seems a bit much to add on the idea that they're essentially the only ones that will do imaging correctly.



128x128twoleftears
tomic601's avatar
tomic601
12,911 posts
 
agree that real engineering is about managing the trade space...however IF we are interested in moving forward instead of creating new flavors, perhaps we can agree that lower distortion is better ?
audiokinesis
2,737 posts
 

@tomic601 wrote: "reflected wave off baffle creates constructive and destructive interference, seen as amplitude....."

A wave travelling along a surface, parallel to that surface, does not reflect off of it. However it can diffract at the edge. The amplitude disturbance caused by diffraction, in and of itself, is imo not a big deal. It is only present in the first-arrival sound so its subjective impact is relatively minor in most cases. However what IS a big deal is, the time delay. The ear is often pretty good at overlooking a distortion that occurs at the exact same time as the signal, but usually quite poor at ignoring a distortion that occurs even slightly later in time. This has to do with a psychoacoustic phenomenon called "masking" which I can come back to if you are interested.

Tomic601 also said, "IF we are interested in moving forward instead of creating new flavors, perhaps we can agree that lower distortion is better?"

I think we should try to figure out which distortions matter the most to the ears and prioritize accordingly. "Lower measured distortion" does not necessarily correspond to "lower perceived distortion". The latter is what matters in my opinion.

Duke

tomic601's avatar
tomic601
12,911 posts
 
Duke: hence my blackart comment... much harder to figure out with reliability psychoacoustics than the more or less well understood physics... Werner H not withstanding....
perhaps it is useful to think of the large baffle as a 180 degree Horn....
and in a two way with crossover overlap easy to see effects of both waves and the baffle...
but an area of violent agreement is the weighted trade space for attacking distortion.... Dr Ottola got us headed down one right path there...
some very simple - like 5 parts in circuit path SS amp outperform tubes in some of the ear is more sensitive areas.....
so that designer understands how we hear and attacks the sensitive stuff first.
best to you Duke
tomic601's avatar
tomic601
12,911 posts
 
great thread has me reading some old and new papers and thinking about ( anything is possible with a third Margarita and some good Jazz ) brushing up on my partial differential equations......

well

maybe not....

can we agree humans can hear + / - 5 db ? 1956 paper, Olsen....
time to get tge old Focal fiberglass spheres out......
audiokinesis
2,737 posts
 

@tomic601 said, "much harder to figure out with reliability psychoacoustics than the more or less well understood physics... "

Psychoacoustics is fascinating, in my opinion, in part because much of it is counter-intuitive.

Sounds like you already have a good background in acoustics (you are absolutely correct that the front baffle is a 180 degree horn!!). You might enjoy Floyd Toole’s book "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms."   His book is basically all about answering the question, "what really matters?"

Best wishes,

Duke

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